But they photograph very nicely. And since that's what most fans do when they visit the model, how is that a problem?

At no time in the production of Trek TOS did the Enterprise look even remotely like that. And fans are supposed to be grateful?

And, no doubt, it can be repainted in a flat grey again next time it's restored. But pics taken of that harshly lit model, as it appeared from the 70s till 1991, weren't very flattering. It wasn't possible to light it the way that it would be lit for SPFX shots in the 60s.